Add Issue #28 superpowers AgentOS verify script (L0-L3a)

[shaun0927]

Summary

• Adds scripts/verify_issue28_superpowers.sh, the first tracked verify script for the Superpowers plugin AgentOS assimilation (Epic: Expose every Superpowers skill as an Ouroboros-native agentOS command #28).
• Reproduces L0 contract+tests, L1 plugin lifecycle+trust, L2 invocation/artifacts/provenance/audit, and L2b destructive-described workflow guard in a single idempotent run on an isolated worktree of origin/main.
• Opt-in RUN_L3A=1 switch launches ouroboros auto --skip-run in the background with a 7-slot-filled prompt and --max-interview-rounds 6.
• Pulls every evidence artifact (env capture, install/inspect/trust logs, audit JSONL, provenance, run-artifact bundle, schema-validation reports, summary.md) into a single timestamped evidence root, matching the patterns used by the in-flight verify scripts for Epic: Assimilate GSD into the AgentOS ecosystem #30 / Epic: Assimilate Compound Engineering into the AgentOS ecosystem #31 / Epic: Assimilate SuperClaude into the AgentOS ecosystem via an Ouroboros plugin #32.

Test plan

• bash -n scripts/verify_issue28_superpowers.sh — syntax clean.
• bash scripts/verify_issue28_superpowers.sh against origin/main 67f776d:
  • L0 PASS — 23 plugin manifests, 27 unittests, compileall clean.
  • L1 PASS — install→inspect→trust→inspect→list against isolated cache/home/trust root; plugin.trusted audit events schema-valid.
  • L2 PASS — 6/6 run artifacts; audit events plugin.invoked / plugin.permission_used / plugin.completed schema-valid; provenance carries all 5 upstream fields; raw_goal_stored and raw_input_stored both false.
  • L2b PASS — finishing-a-development-branch handoff carries the report-only guard.
• L3a re-run with --max-interview-rounds 8 + 7-slot-filled prompt — BLOCKED at ambiguity 0.228 by ouroboros/auto/safe_defaults.py::_unsafe_context_reason firing on deploy inside the user's own non_goals: body. Not a Superpowers plugin failure. Root-caused upstream and fixed in Q00/ouroboros#1221.
• Dispatcher leg — ouroboros <plugin> <skill> IS implemented in CLI v0.39.1 (cli/main.py:_PluginAwareGroup + cli/commands/plugin_dispatch.py, via OUROBOROS_PLUGIN_LOCKFILE / OUROBOROS_PLUGIN_TRUST_ROOT env overrides). Earlier "dispatcher missing" finding was retracted in #28 verdict update. A follow-up commit will add a dispatcher leg to the verify script that exercises the same end-to-end path through ouroboros superpowers <skill>.

Upstream dependency

L3a closure for this verify script (and for #30 / #43 / autoresearch / github-pr-ops L3a) depends on Q00/ouroboros#1221. Once that ships in ouroboros-ai, re-running RUN_L3A=1 bash scripts/verify_issue28_superpowers.sh should produce an A-grade Seed.

Refs #28.